Both Corn stalk and wood are renewable lignocelluloses resources accumulated by photosynthesis, but wood is used widely, while most of corn stalk is incinerated or discarded. It is the most important reason that the corn stalk is of heterogeneity, which contains peel, pulp and leaves and so on in certain proportion, and with different chemical compositions and fiber morphology. The corn stalk used in the present invention is respectively produced in Yanshou county, Heilongjiang Province and Gongzhuling, Jilin Province. Analysis of the two kinds of stalk is showed in the following table, as the amount of leaves and pulp takes up more than 60% of the total corn stalk. The corn stalk leaves have low mechanical strength, and could be crushed into powder easily; the corn stalk pulp has low density, high hydroscopicity and low mechanical strength; the peal has the highest fiber content and the highest mechanical strength in all parts of corn stalk, but the quantity is relatively low. At present, the comprehensive utilization of corn stalk is still in the low level in terms of the degree of the process. The fiber with high mechanical strength and good toughness is only found in the corn stalk peal, while the nutrient contents are found in the corn stalk leaves and pulp. In normal conditions, the outer peel and the inner pulp of the corn stalk are mutually interfered, so it is difficult to have new applications. Therefore, how to separate the peel and pulp, extending its applied fields, improving its application performance and raising its value has became the key factors comprehensive utilization of corn stalk.
Mass fractionCorn stalkCorn stalkcorn stalkOriginleavespeelpulpGongzhuling, Jilin Province52.930.716.4Yanshou county, Heilongjiang49.235.215.4ProvinceAverage51.232.915.9
CN102490238A discloses a method of processing the corn stalk about separating the corn stalk peel from the pulp. The invention solves the technical problems of the mutual interference of the outer peel and the inner pulp of the corn stalk; and the quality of the plate material prepared by the corn stalk is reduced to a large extent because of the existence of the pulp. The method includes the following steps: 1. smashing the corn stalk primarily separated by the traditional separator; 2. removing hard parts and dust of the smashed corn stalk by screening; 3. smashing the smashed corn stalk processed in the step 2 again, then drying; and 4. screening the smashed corn stalk processed in the step 3 by 10-50 meshes point, then winnowing the smashed corn stalk went through the different meshes to separate the corn stalk peel from pulp. The final peel purity of the smashed corn stalk peel is more than 90%. Therefore the obtained peel is suitable to serve as a raw material used for producing the plate of the smashed corn stalk peel.
It is reported that, after separation of peel from pulp, the peel having high lignocelluloses content which can replace wood, reeds, etc. and is suitable to serve the raw material for papermaking. Pulp containing more sugar, protein and starch can be used as the super roughage for ruminants such as cows and sheep.
The effect of present separator is not ideal. The corn stalk need to be assembled before separation, large amount of manpower and material resources are wasted, also the corn stalk is not utilized enough.
The storage of the corn stalk also has many problems. At present, the main storage methods of the corn stalk include outdoor storage, shed storage, drying, sun drying, silage, micro storage or ammoniation, etc. The methods for storing the corn stalk by drying and shed storage are advantageous for the preservation of the CP (crude protein) and the other nutrients likewise the WSC. And outdoor storage is the most undesirable way. At present, there are the following problems in micro storage of the corn stalk: {circle around (1)} Temperature: The micro storage is often operated after the busy farming season, when the field crop has been harvested and storied. It is generally around the middle of November when temperature is below 0° C. with bad climate for the breed and fermentation of lactic acid bacteria species; {circle around (2)} Water: The content of corn stalk water is not accurately considered as adding water, while the moisture required in the process of micro storage lacks of scientific calculation and strict control; {circle around (3)} Bacterial pollution: In the process, it is hard to achieve quick storage. The process could even last a few days, and increase the pollution probability by other kinds of bacterial. {circle around (4)} Sealing: If the corn stalk is not compressed enough in the process of loading pit, breathable and leakage phenomenon would occur after the pit was sealed up. {circle around (5)} Workforce: The operation of micro storage, silage and ammoniated are often operated after the busy farming season, when the crops have been harvested and storage. Farmers are busy with the harvesting, and have no time to collect, transport and do other basic work of micro storage, silage and ammoniated. © When the moisture content of the harvested corn stalk is above 70%, compress and package would cause mildew. Whole plant transport would cause less loading capacity and more transportation costs.
Kneading technology and baling technology are new processing methods of the corn stalk in recent years. The kneading technology for the corn stalk changes the traditional transverse cut into the longitudinal kneading. And the corn stalk is processed into soft filamentous forage grass. The epidermis structure of the corn stalk is destroyed after kneading process; the forage grass could get soft and have good palatability. Therefore feeding rate can be improved.
However, the above techniques are only used in making the corn stalk into the forage grass by kneading, which greatly limits the application range of the corn stalk. In addition, the pulp is not removed by the kneading technology, so all of the corn stalk pulp exists in the soft filamentous grass prepared by the corn stalk. The pulp contains a certain amount of xylans hemicelluloses, which could be oxidized into carbonyl chromospheres or carboxyl auxochromes by light and oxygen. If the soft filamentous grass is used in papermaking, it will cause serious yellowing phenomenon. Otherwise, as the pulp is brittle, the existence of pulp will cause paper tear index decline in some extent.
Therefore, the separation of the peel, pulp and leaves on a large scale to provide a performance improved corn stalk material, extending its applied fields, improving its properties and raising its values will be the key factors comprehensive utilization of corn stalk.